diff --git a/lib/pry/config/lazy.rb b/lib/pry/config/lazy.rb
index e63f2862..fc3eb101 100644
--- a/lib/pry/config/lazy.rb
+++ b/lib/pry/config/lazy.rb
@@ -1,6 +1,5 @@
 module Pry::Config::Lazy
-  LAZY_KEYS = {}
-  LAZY_KEYS.default_proc = lambda {|h,k| h[k] = [] }
+  LAZY_KEYS = Hash.new {|h,k| h[k] = [] }
 
   module ExtendModule
     def lazy_implement(method_name_to_func)